I read that once every second, somewhere in the universe a massive star ends its life as a supernova. How does that compare to the rate of new star formation?

Let’s look at the rate of new star formation nearest to us — in our galaxy. Technology allows astronomers to see the Milky Way’s individual stars, so they can count all the suns, measure their ages, and measure their brightnesses (which are related to their masses). A few years ago, scientists used the Spitzer Space Telescope to study the Milky Way’s plane — where nearly all new stars form — and found a birth rate of 0.68 to 1.45 solar masses per year. As an average, researchers typically say our galaxy is converting about one Sun’s worth of material into stars each year.

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